Power shift transmission



25, 1938 i O K, KELLEY 2,106,608

POWER SHIFT TRANSMISSION Filed Feb. 24, 1936 3.Sheets-Sheet 1'- Jan; 25, 1938. 0; K. KELLEY- 2,106,608

POWER SHIFT TRANSMISS ION Filed Feb. 24, 1936 s Sheets-Sheet 2 I. I I II I I l I I I. "Q I 4' I I I I I N I I I l I l' I l I k I I I Q I I Q I w I I 3 I I 4 I I "3 I I I 7 I I a I' I I i @ZE/fflf' 31 /16? Jan. 25, 1938.

Filed Feb. 24, 1925 MI I 3 Sheets-Sheet 3 Patented Jan. 25, 1938 I UNITED STATES PATENT OFFICE sham rownn smr'r mansrnssron Oliver K. Kelley, Pontiac, Micln, assignor, by

meane assignments, to Yellow Truck and Coach I I I Manufacturing Company, Pontiac, Micln, a

corporation of Maine Applicatioml ebruary 24, 1935, Scrial No. 65,221 13 mm. ((174-364) This invention has to do-wlth power shifted change speed gear transmissions for motor vehicles.

In the conventional manuallyshifted automobile transmission, a hand lever extends upwardly from the gear box to a point within convenient reach of the car driver,'and a side movement of the lever selects oneof a series of shift rails and then a forward or rearward movement shifts the rails for eifecting a given speed setting. Where the transmission is located at a point remote from the drivers station, as in the case of a rearwardly mounted power plant in a bus, a fluid pressure system is used for transmitting hand lever movement, or more properly speaking, for setting the gears in accordance with the position to which the hand lever 'is'moved.

One of the most popular of such systems is that shown. in French Patent No. 781,511, issued to Bendix Westinghouse Automotive Air Brake Company, wherein the hand lever controls a series of valves from which air under pressure is fed through conduits to pressure responsive devices associated with the transmission unit for effecting speed changes. One of the pressure responsive' devices acts to move a selector arm transversely of the shift rails into selective engagement with the rails and the other pressure, re-

. sponsive device acts to shift a selected rail axially;

It is to a transmission of this sort that the present invention relates and the object of the invention is to improve the operation of'the shifter system and insure the transmission of drive through the gear box in the speed setting to which the hand lever is positioned.

. For a better understanding of the invention it is pointed out that the mentioned air'shift system j The objection to'the system is that in changing from one speedsetting to another, except for a change which involves second speed setting, the

' and 3,*respectively. The end of the input shaft plete'return of the gear parts from the previous setting.- Attempts to shift rapidly may prevent the shifter am moving free of the shift rail con- 1 trolling the previous setting and the reapplication of power returns the parts to the previous setting.

There-is no trouble regarding successive shifts which include the second or intermediate speed setting, inasmuch as the successive movements of the shift rail then is alternately in opposite directions. The real danger involved through careless or inexperienced handling, is most-likely to result in changing between reverse and low speed settings. In other words, if the .vehicle has been running either forward or backward and it is desired to change the direction of travel, unless care is exercised in operating the hand lever controlled valving, travel in the previous direction may be resumed despite a change in hand lever setting.- I 0' Accordingly, it is proposed, as regards shifting into reverse and first or low forward speeds, to interrelate theaction of the pressure responsive devices in a way that shifting cannot occur until after rail selection is complete. This will make the operation fool-proof and not only will there be eliminated the possibility of injury and damage because of a vehicle movement in a direction not intended, but in addition the operator will be relieved of care and mentalstrain.

So much of the system as is necessary for an understanding of the invention ,is illustrated in the accompanying drawings, wherein Figure 1 is a more or less diagrammatic view of the operating mechanism and the assembly of pressure lines; Figure 2 is a section taken on line 2-2 of Figure 1" and Figure 3 is a sectional view to illustrate a part of the operating. mechanism in detail.

In the drawings the reference numeral i indicates a gear box to containvariable speed gearing of any conventional type and which transmits the drive from the engine to the road wheels. -A portion of the gearing is illustrated in Figure 2 where the input and output shafts are indicated at 2 carries a gear 4 adapted for constant mesh engagement with a gear on a countershaft, not' shown. This countershaft, as will be understood,

operator must move the hand lever to neutral position and then delay its movement into the next position a sufficient interval to allow com.-

constant mesh engagement with cooperating bearings on the output shaftin spaced relation, ,with'the gear element 4. Tubular projections 8 carries a series of spaced gear elements each in 50 gearing adapted for drive engagement with the 7 output shaft. The second speed gear' of the train is indicated at 5 as being mounted upon suitable a shift rail- I4. Additional shift rail and I on the gears 4 and B, respectively, are each provided with internal clutch teeth adapted for independent engagementwith external teeth on a clutch slidercollar I which is keyed to the output shaft. In Figure 2 the slider is shown in an intermediate orneutral position. Its movement toward the right will clutch it with the extension 1 toeifect second speed drive while its movement toward the left will engage the extension 6 for directdrive relation.

Associated with the slider 4 is a sleeve ll whic carries speed synchronizing cone clutches at opposite ends for engagementwith cooperating conical surfaces on the gear elements 4 and I, whereby equalization of speeds is effected to facilitate engagement of the clutch teeth. 'Secured to the slider l at circumferentially spaced points by swinging arm I! into engagement with any one of'the several shift rails.

Axial movement of the selector rod it acts through, the selector am i! to move the shift rail engaged thereby to control the setting of the change speed gearing. The rocking and shifting of the selector rail II is effected through pressure responsive devices. One of these devices includes as an assembly, a cylinder I! and a piston 20, the piston having a rod 2| extending therefrom for sliding keyed engagement with a feather 22 formed as a part of the selector arm II. me

= other pressure responsive device includes a pressure cylinder 23 in which isslidable a piston 14 mounted on one end of the selector rail IS.

The other end of the selector rail l4 carries. a

hollow valve casing 25 and a lever is pivoted thereto by ,a stud 21 to control the action of a pair of valves located on opposite sides of the pivot connection-s Set screws 28 and 1| on the lever are provided for engaging the valve elements. This mechanism forms part of a well I known follow-up system controlling the flow of airunder pressure to thepiston cylinder 28. Itincludes in addition, a piston cylinder I0 enclosing a piston M which is connected as at u with the lever 28. Coil springs "-83 on opposite sides of the piston tend to maintain a centered relation of the parts and each spring seats on a slidable abutment 14 which limits the expansion of the spring so that the springs act in opposition to each other only when the piston is in centered position.

Air under pressure introduced into the cylinder a on' either side of the piston u will swing the lever 28 about its fulcrum connection 21 with the shift rail I8 and open 'one or the other of the valves associated with thehousing II. This will allow-flow, from a storage tank 88. or-othersuitable source of air uhderpressure. through a con' duit 84 connectedwith'the interior ofthe hollow yalve casing 2| and-through one. or the other of i thWduitsil-fl whichlead to the .piston cylinderflll 'oppositesides oi the piston 24; The

respbnseofthe piston 24 to prcesur'e shifts the rail it and necessarily carries with it thgjelvt tel-mediate speed setting;

casing and the lever 26 and the movement of the fulcrum-point21-for the lever 26, necessitates continued movement of the piston 3| to keep the valve open. Each of the follow-up valves may be constructed as shown in the detail view; Figure 3, where the set screw is shown in engagement with a piston 40 slidable within an air chamber which communicates with the conduit 31, and the inward movement of the piston unseats a valve disc 4| for the passage of air from the hollow interior of the casing to which the pressure line 36 leads. v The air shift system as thus far described is substantially that placed on the market by Bendix Westinghouse and which includes in addition a multiple valve indicated in the drawings at 42 controlled by a hand lever 43 for supplying air under pressure from the tank through a conduit 44 to several pressure lines indicated at 45, 48, 41, and 48. The valve is so constructed as to exhaust any pressure 'line which is not in comihunication with the pressure conduit 44. Whereas in the conventional design'air is fed through the several conduits 45-48 in various combinations according to the speed setting desired. it is here proposed for. anyone speedset tins, to use but one pressure line. For identification, the conduit 45 controls. first or low speed setting, the conduit 48 controls reverse speed=setting, the conduit 41 controls third on high speed setting and the conduit 48 controls second or in- For second speed setting the shift 'movedto proper position to flow air under pressure through the line 48 and into the left-hand end of the piston cylinder 30 as seen inthe drawings. The movement of the piston 31 toward the right permits air flow through the conduit and into the left-hand end of the p on cylinder 13 which correspondingly shifts the all l4 to engage the clutchteeth of the parts I .a d 8. For third speed setting air under pressure flows through the line 41 to the interior of a-valve casing to be later described, and which is coupled by a nippie 5. to the right-hand end of the pressure cylinder 3.; This moves the piston to the left and 'actuates the follow-up valve to flow pressure through the conduit 31 into the right-hand end 'lever 4! is I of the pressure cylinder 23 and correspondingly move the piston 24 and with it the associated parts to effect high speed setting.

During the second speed and third speed operation both'sides of the selector cylinder I! are exhausted and the piston II is held in an intermediate position by centering springs BI and 62, whereby the selector finger engages with the intermediate shift rail l4. Coming now to-the reverse and low speed. settings and taking these u up in order, the flow of air under pressure through the line 44 causes the piston 20 to be moved toward one limit of its travel and by reason of the connection between the piston rod-2i and the selectorarm I1, therail I! is rocked about its axis and the selector arm i'l swings through the alined slots it into engagement with the reverse speed selector rail. As the selecting operation reaches completion the piston 20 uncovers a port It inthe boss 44 formed on the piston cylinder it, to allow the flow of air under 12 ugh the conduit 8'! for moving the piston 24 (l with it the reverse speed shift rail. In a similar manner, first speed setting is effected when air flow through the conduit .45 moves the piston 20 toward the other limit of travel to first swing the selector arm ll into engagement with the first speed shift rail and thereafter uncover the port 53 to allow fiow through the conduit 55 into-the right-hand end of the piston cylinder 30 for again actuating the follow-up valve' which controls air flow through the conduit 31.

Thus it will be seenthat the direction of movement of the several shift rails for first, reverse and third speed settings is the same, but inasmuch as .the shift into first and reverse speed settings cannot be made until after selection is complete, proper engagement of the gearing will result without the need for special care on the part of the operator in his manipulation of the hand lever 43.

The valve casing 49 is provided to insure proper exhaust and to direct air. under pressure to the cylinder 30 upon its supply through the independent lines 41 and 55'. As seen in'Figure 3 the hollow. casing encloses a plate valve 58 held on its seat by a coil spring 51' and provided centrally thereof with a slidable plug 58.. A flexible diaphragm 59 prevents leakage between the plate 56 and its plug 58. The plug is adapted to seat over either of the alined ports 50 and GI in the opposite sides of the casing A5 and with which communicate, respectively, the pressure lines 41 and 55. Upon the application of air under pressure through the line 55, the plug 58 is moved toward the right and seats over the port 60 to prevent the escape of air through the vented conduit 41. It also moves. the plate 56 against the spring 51 and the air flows from the casing 49 through the nipple 50. Upon the relief of pres- .surethrough the line 55, the spring 51 restores the plate 56 and eliminates reverse flow of air through the line 55 toward the piston cylinder l9.

Any air pressure remaining will move the plug- 58 awayfrom the port 60 for exhausting the cylinder 30. On the other hand, when air under pressure is supplied through the line 41 it seats the plug 58 over the port N which in cooperation with the plate 56 provides a double guard against leakage of air through the conduit 55. haust of airfrom the cylinder 30 occurs as before described. a

I claim: a

1. In a power shift transmission of the characted described, a series of shift rails, means. selec vice to shiftthe rail, a piston connected with the tively engageable with the rails to shift the same. a pair of pressure responsive devices 'associatedwith the selector means to operate the same, a source of fluid pressure, means communicating one of said .devices with the pressure source and means-controlled by a predetermined response of the last mentioned device .to communicate the other device in series relation therewith.

2. In a power shift system, a rcckahle and shiftable selector rail, a pressure responsive derail to rock the same, a cylinder slidably containing said piston, means on opposite sides of the piston to introduce fluid under pressure into the cylinder to move the piston in one direction or the cther'from a centered position and means cornmunicating the pressure responsive device with the cylinder after the piston has moved in either direction from said centeredposition- 3. Gear shift mechanism including a rockable andshiftable speed'selector rail, a pressure responsive device for shiftingsaid rail, a pressure responsive device for rocking said rail, means for The exsupplying fluid under pressure to the last mentioned device to rock said rail and means controlled by the action of said device and effective after a predetermined response, to supply fluid under pressure serially from said device to the first mentioned pressure responsive device. 5

4. The combination with gear shift rail selector mechanism and rail shifter mechanism adapted for action in sequence, of power supplymea'ns for operating said mechanisms, a conduit. con-' from one to the other, means for connecting the power supply meanswith one of said mechanisms and means dependent upon the response of sai mechanism to open said conduit. r

'5. Ina power shift transmission, a movable shifter element, a pressure responsive device to move the element in one direction, pressure responsive means to move the element in a direction transverse to the direction of the. first mentioned movement, including a piston and cylinder assembly, means to introduce fluid under pressure into the cylinder on opposite sides selec tively of the piston, a port in the cylinder adapted. to be closed by the piston when the piston is in amintermediate position in its range of movement and to be uncovered and opened to the pressure side of the cylinder when the piston reaches either limit of its movement, and a fluid. pressure conduit connecting said port with the 'pressure responsive device for the sequential ovement of said shifter element in angularly related directions.

.6. In a power shift transmission having a series of shift rails, a selector rail adapted for transverse movementinto selective engagement with said shift rails and for axial movement v a selected rail, a pair of pressure responsive devices associated with the selector rail to impart.

the respective movements thereto, means tosupply pressure fluid to thedevice for eflecting transverse movement of the selector rail, means effective after apredetermined response of said a device to supply presure fluid therefrom to the other device, additional meansto supply pressure fluid to the last mentioned device independent'of the first means and a pressure actuated valve associated with both supply means to said last mentioned device and active when fluid pressure is supplied from either of the two supp means, to close the other thereof.

. '8. In a power shift transmission having a series of shift rails, a selector rail adapted. for transverse movement into selective enga ement with said shift rails and for axial movement with a selected rail, 9. pair of pressure responsive devices associated with the selector rail to impart the respective movements thereto, means to supply pressure fluid to said'devices including a se- -ries of conduits and a valve element comprising a casing having a hollow chamber-communicat with one of said devices, a pair of spaced val e seats. mi: associated with separate pres- 10.. nectlng. said mechanisms for the flow of power associated with the other conduit.

9. In a fluid pressure controlled variable speed transmission, a source of fluid pressure, a fluid pressure operated shifter mechanism and a fluid cluding a'piston and a cylinder and the cylinder cylinder, and a conduit connecting said port with pressure operated selector mechanism adapted for series connection with the fluid pressure source, said fluid pressure selector mechanism inhaving a port in the wailthereoi adapted to be covered by the piston in one position thereof and to be uncovered upon movement of the piston under the application of fluid pressure to the the shifter mechanism for flow of pressure fluid from the pressure side of the piston after the port is uncovered. p

10. In a power shift transmission, a source of power, a power actuated 'selector mechanism adapted for direct connection with the power source. a power actuated shifter mechanism, means for connecting the shifter mechanism directly with the power source independently of the power connection to the selector mechanism, and other means for connecting the shifter mechanism with the power source in series relationwith the selector mechanism after a predetermined response of the selector mechanism.

11. In a power shift ton, a source of powenpower actuated selector and shifter mechanisms adapted for serial connection with the power source, said selector mechanism being intei'posed in the connection between the shifter mechanism and the power source and including" thereto and means operable after a predetermined relative movementof said member to feed power from the power source serially through the selector mechanism to the shifter mechanism,

12. 'In a control mechanism for a vehicle gearing apparatus having a selector and shifter member normally occupyin a neutral position, means for mounting said member adjacent said apparatus, a fluid power operated device for oscillating said member in either of opposite directions to select a desired gear ratio, a separate fluid operated device for shifting said member to establish the selected gear ratio, manually op-' erable means to control the application of fluid pressure to said first device, and means controlled by the operation of said first device for establishing communication between said second device and said manually operablemeans whereby fluid pressure is conducted to the second deoperated device for shifting said member to es-- tablish the selected gear ratio, manually operable means to control the application of fluid pressure to said flrst'device, and means rendered operable by movement of said first device for establishing direct communication between said second device and said manually operable means whereby fluid pressure is conducted to the second device.

- OLIVER K. 

